Process of tanning hides



Patented July 31, 1928 UNITED-STATES KURT H. MEYER AND HERMAN N SCHlI TTTE, OF MANNHEIM, GERMANY, ASSIGNORS To I. G. FARBENINDUSTRIE AKTIENGESELLSCHAFT, OF FRANKFORT-ON-THE-MAIN,

GETtMANY.

PROCESS OF TANNING RIDES.

No Drawing. Application filed October 27, 1924, Serial No. 746,248, and in Germany November 14, 1923.

This invention relates to the use of artificial tanning materials in tannery and consists in the valuable discovery that sulfonic acids obtained from lignite tar which is pro- 5 duced by the carbonization of lignite at low temperatures, or from low temperaturecarbonization tar from other rarities of coal, which products may be comprised by the term aliphatic tars, or from fractions thereof, have very good tanning propertiesv and may be applied for treating hides or skins either alone or in conjunction with natural or other usual tanning materials. The leather thus obtained has very good properties, especially good body and.

Example 1. 3 parts of a tar oil obtained from lignite (brown coal) tar by fractional distillation and by separating solid paratfin bycooling,

, is mixed with from 3 to 4 parts of concen-' trated sulfuric acid of 66 degrees Baum and the mixture is vigorously stirred at a'moderately raised temperature. After a While, the mixture is poured into ice water and the un altered oil separated from the acid .solu

tion, which latter is'neutralized with lime,

filtered and decomposed with sodium carsolution.

I Ewample 2. 4 parts of low temperature carbonization bonate. It is then ready for tanning which is done in a slightly acidulated and diluted thick tar and from 5 to 6 parts of monohydratic sulfuric acid are vigorously stirred for several hours at a moderately elevated temperature. The sulfonation mixture is worked up as described in Example 1 and the product can be used for tanning in the usual manner employing it in a dilute slightly acid aqueous solution. The product may be used either alone 'or in mixture with other tanning substances.

\Vhat we claim is: a

1. The process of tanning .wZhich consists in treating hides with a slightly acid solution containing a sulfonation product of an aliphatic tar.

2. The process of tanning which consists in treating hides with a slightly acid solution of a sulfonation product of a fraction of-an aliphatic tar. I

3. The process of tanning which consists in treating hides with a slightly acid solution containing a sulfonation product of an aliphatic tar and a usual tanning material.

4. Asa new tanning composition a slight 1y acid solution containing a sulfonation product of an aliphatic tar. I

5. As anew tanning composition a slightly acid solution containlng a sulfonation product of a-fraction of an aliphatic tar.

6. As a new tanning composition a slightly acid solution of a sulfonat-ion product of 7 an 1aliphatic tar and a usual tanning matcria 7. As a new tanning composition a slight 1y acid solution containing a product ob' tained oy-the sulfonatio-n of the distillation so products of low temperature carbonization tars.

In testimony whereof we. have hereunto set our hands.

' .KURT H MEYER: HERMANN soHUTTE. 

